The present disclosure relates to a communication system, a communication control device and a communication control method that enable communication between terminal devices that are subordinate to NAT devices.
There are cases in which Peer to Peer (P2P) communication is performed between terminal devices that are subordinate to different devices that are equipped with a Network Address Translation (NAT) function (such as a NAT router etc. Hereinafter, the device equipped with the NAT function is referred to as “NAT device.”) In this case, it is necessary for the terminal device to identify a port number stored in the NAT device and transmit a packet addressed to the identified port number. A method is known in which a server device manages the port number stored in the NAT device, and the terminal device acquires the port number from the server device.